Improvement in safety-valve regulators



` UNITED STATES PATENT OFFICE.

IMPROVEMENT IN SAFETY-VALVE REGULATOPLS.

Specification forming part 0f Letters Patent No. 46,142, dated January3l, 1865.

To all whom 'it may concern:

Be it known that I, PETER RIORDAN, of of the city and county ofWashington, in the District of Columbia, have invent-ed a new and usefulImprovement in Safety-Valve Regulators for Steam-Boilers; and I dohereby declare the following to be a full and exact description ofthe'same, reference being had to the accompanying drawings, making partof this specification, in which- Figure l is a side elevation of myimproved safety-valve regulator. Fig. 2 is a longitudinal section of thesame, and also a sectional view of the parts which afford communicationbetween the regulator and boiler.

Similar letters of reference indicate corresponding parts in the severalfigures.

The object of this invention is to provide novel and simple means forindicating the amount of pressure which the steam exerts upon theboiler, and for reducing such pressure when it becomes excessive, aswill be hereinafter fully explained.

To enable others skilled in the art to which my invention appertains tofully understand and use the same, I will proceed to describe itsconstruction and operation.

In the accompanying drawings, A A represent a cylinder, into which steamis admitted from a steam-boiler through the apertures a a. The part A ofthe cylinder is of larger diameter than the part A', and in said part Ais iitted a circular head, B, which is formed on or secured to the upperend of a shaft or stem, C. 'lhe other end of the shaft O carries a head,B', which works in the part A of the cylinder, and is consequently ofsmaller diameter than the head B. Oonjoined to and extending upward fromthe head B is a hollow shaft, D, which, when the heads B B/ are inmotion, is adapted to work through a suitable stuffing-box orsteam-tight bearing in the end ot' the cylinder.

E is a spiral or other spring, placed within the hollow shaft D in themanner represented, and having aiiixed to one of its ends a valve, F,which, when in its normal position, closes egress-apertures el d' in theshaft D. Steam may enter the shaft D through the apertures d d. Thepower of the spring E in resisting the pressure which the steam exertsupon the valve F may be varied by the contraction and extension of thespring itself, and this can be effected with facility by turning the nutor collar G, which works on a threaded part ot' the hollow shaft D. Thelatter may also be graduated, in order that the position of the collar Gmay indicate to the eye the exa-ct `amount of pressure which the springE enables the valve F to withstand before being moved, so as to uncoverthe apertures d.

The heads B B form tightjoints with the sides of the cylinder A A', andthe space between the two heads is occupied by air, no steam havingaccess thereto.

When the engine is not in operation, the head B will, through theinfluence of gravity, assunze such a position as thesafety-valve sittingin its seat, and the length of the hollow rod D, which is connected atthe upper end with the lever of the safety-valve, will allow, and thislength must be made so as that the head B will be near the bottom of theupper or large part, A, of the cylinder and the apertures d d withoutand a little clear of the stuffing-box. Vhen steam is generated in theboiler and admitted through the apertures a a, the pressure of the steamon the upper face of the head B is greater than the pressure on theunder face of the head B by as much as will, when there is anequilibrium of pressure on both and on the safety-valve, counterbalancethe effective lifting force of the safetyvalve on the safety-valve leverthat is attached to the hollow rod I), this result being effected by thedifference between the eective areas of the heads B B. The nut or collarG is then screwed down and adjusted by the graduated face to control anyspecific pressure on the valve F, which only slightly covers theapertures d d. ,k

As long as the pressure on the boiler, and consequently in the cylinderA A, does not exceed that at which the spring is set to control, thesafety-valve is held down, and does not blow oi' any steam; but when thesteam in the boiler exceeds this pressure, it, entering the hollow shaftD through the apertures d d, forces up the valve F and escapes into theair through the apertures d' d', so that the pressure on the head Bcannot exceed that-at which .the spring is set to control, while thepressure on the head B increases in the same ratio as that in theboiler, the effect of which will be to lessen the holding-down power ofthe steam on the head B by as much as the pressure of the steam on A isgreater than on A', and consequently allow the safety-valve to blow oi'much sooner and faster than usual, and thus preserve a more uniformpressure in the boiler. For example, if the lifting-power of thesafety-valve on the end of its lever attached to the end of the rod D betwentyive pounds when the pressure on the boiler is fifty pounds on thesquare inch, and if the area of the head B, on which the steam exert spressure, be two square inches, the area of the head B', on which thesteam acts, must be one and a halt' inches. Now, the total effectivepressure at fifty pounds to the square inch on the head B will be onehundred pounds,

while that on B will be seventy-tive pounds,

but when the steam gets up to a pressure of iit'ty'one pounds on thesquare inch in the boiler thatin the cylinderA blows otl" through d d',and cannot exceed one hundred pounds, while that in A becomesseventy-six and a half, and consequently lessens the holding'- downpower of' B by one and a halt' pounds, or from twenty-five pounds totwenty-three and a halt', and thus the safety-valve blows off withincreasing rapidity as the pressure in the boiler gets up.

Haying thus described my invention, the bllo'wing is what I claim as newand desire to secure by Letters Patenty 1. In combination with acylinder formed in two parts, A A', of different diameters, thepiston-heads B B', when so arranged that the effective area of the headB on that side next thel steam'port a, eXreeds the effective area of thehead B on the side next the port a by as much as the area of thesafety-valve divided by the number of times by which the length of thelong,` arm of the safetyvalve lever eX- ceeds that of the shoit arm.

2. rThe combination of the valve F, spring` E, and adjustable nut orcollar G, with the hollow-graduated shaft D and apertures d, the wholebeing` arranged and employed substantially as and for the purpose setforth.

PETER BIORDAN.

VitnesSes:

CHARLES D. SMrrrr, EDWARD H. KNIGHT.

